The Molecular Epidemiology in Children's Environmental Health (MECEH) training program began July, 2001 and is in its tenth training year. MECEH is defined as the use of biological, molecular and statistical measures in epidemiological research to determine how environmental exposures impact children's health at the physiologic, behavioral, cellular, and molecular levels. As the offspring of epidemiology, medicine, statistical genetics, molecular biology, and molecular genetics, molecular epidemiology serves as an umbrella for focused research in genetic and biomarker epidemiology. MECEH has 3 participating departments: Environmental Health, Pediatric Medicine and Molecular Genetics. MECEH has had continuous full enrollment with 13 pre-doctoral and 24 postdoctoral fellows trained or in training, including 19 M.D./D.O fellows, one DDS, and one environmental engineer. Trainees have made great professional strides with national presentations, numerous publications, grant submissions and obtaining academic research positions. This application requests support for four pre-doctoral and six postdoctoral positions each year for 2011-2016, which will maintain this program at its current size. The MECEH's long term objective is to continue increasing the number of cross-trained epidemiologists, physician epidemiologists and molecular biologists who investigate high impact issues related to environmental exposures and complex childhood diseases. The overarching rationale for this training program has been stated in such federal initiatives as the Children's Health Act of 2000 (H.R.4365) which stressed investment in tomorrow's pediatric researchers (sec 1002). The MECEH has 3 primary goals: 1) provide a strong grounding in epidemiologic, statistical and wet and dry laboratory molecular methods, 2) prepare students for interdisciplinary research training and enhance clinical research workforce training as stated in the NIH roadmap, and 3) in concert with Francis Collins' direction for opportunities and challenges the investigators seek to expand growth areas for trainee expertise in statistical genomics, epigenetic epidemiology, and design of community based participatory research. These goals are achieved through the recruitment of high quality applicants, including underrepresented minorities, mentorship by a core of world-renowned teacher-scientists, support by research-intensive environmental health, pediatric and molecular genetics departments, well-funded scientific programs and Centers, and advice from an enthusiastic External Advisory Board. The public health significance of the MECEH program is directly correlated to the increasing national awareness of the rising number of environmentally related disease such as diabetes, obesity, asthma, neurodevelopmental disorders, and prematurity, among others. Thus, the